Cockroach Composting

For most people like you and me, composting serves two main purposes – eliminate food wastes biologically rather than wastefully(landfill), and create nice rich nutrients for plants. You can use all kinds of methods to accomplish those goals, and this article is a great example of that. Cockroaches! Yes, cockroaches are incredible composters. Truly amazing, they will eat anything and everything you put in there, reproduce like crazy, and have virtually NO SMELL. I know it’s shocking to think of cockroaches as being a clean detritivore, but it’s true.

I have a Bearded Dragon, Opi, who originally got me into the cockroach thing. Bearded dragons are voracious eaters, and besides the cost I just didn’t want the hassle of going back to the store every week. After doing some research I found roaches an excellent solution to this issue.

The species of roach I got is a standard feeder species, Blatta lateralis, you can buy them in many pet stores or order online. I ordered off a craigslist type site local to the Philippines, went down to the station and met a guy with a bag of roaches.

Disgusting. I agree. I grew up in the country, I love reptiles, amphibians, arthropods, all manner of creepies, but roaches are just disgusting. However! After raising them I can say they really aren’t so bad – I think it’s the no smell thing that makes me feel better.

Anyway, after the meet-up for the bag of roaches, brought them home and a little while later, thriving colony, everyone happy, Opi diving into mounds of the things quite happily, etc etc.

Why I like it, and how to do it

First why I like it. It requires cleaning the whole setup once every 6 months or so. That is after putting all kinds of food in every single day – dog food, people food, nasty moldy food, not-even-food food, whatever. There is NO smell from 2 feet away and I only have to clean the tank every 6 months? I can throw all my scraps in it no matter what they are? It produces insane compost for the garden? Sign me up!

I cleaned out the cockroach composter(aquarium for now) today so I took the opportunity to grab some pictures.

Here is the overall setup before cleaning. This is after about 6 months of doing nothing except adding food and changing the water every few weeks.

The tank before I cleaned it. You can see the feeding area has some bones around.

Cockroaches are prolific breeders. This species lays egg cases(ootheca) at an astonishing rate. Check out the substrate surface before cleaning it – each of those egg cases contains 20-30 eggs, gives you an idea how fast the colony can grow. You can also see some chicken bones, fish bones, a little stick of bamboo – leftovers from feeding. No need to remove these things as they will be great in the compost pile or garden.

Close-up of the substrate…except you can’t see the substrate for all the egg cases.

The bin attracts various creatures. This type of beetle(some type of darkling beetle I think) invaded and went crazy in there, there are almost as many of them as there are roaches. The beetle larvae burrow around in the substrate and eat up everything the roaches don’t and they seem to get along fine so whatever. Don’t fight nature if you don’t have to! As unconventional farmers, we are working with nature as much as *humanly* possible, haha.

The invader – I think a darkling beetle species. They reproduce like crazy but get along great with the roaches so whatever.

The bin also attracts larger creatures though, such as sparrows and geckos. I finally had to put a lid on the bin to keep the sparrows (I have roaches to spare, as opposed to my beautiful sprouts they trashed on the other balcony) out because they were trashing it trying to get at the roaches. I love attracting nature to the balcony, I was sad I had to lock the birds out but at least the geckos can still get in and get their fill. The birds came a few days and then figured it out:

The predators. I finally covered the top of the cage because the birds were tearing it up a bit.

After 6 months the bedding is insanely rich over under the food area. It is moist and thick, full of nutrients from 6 months of cockroach frass and decomposed organic matter. You can see the darkling beetle larvae, pupae, and a few adults:

Look how rich that soil is! It used to be coco coir but now it’s unrecognizable. There are some egg cases and beetle larvae visible too.

The darkling beetles even core out the chicken bones so they end up being hollow – perfect home for microbes and roots. With the roaches temporarily in a black plastic garbage bag (new egg-carton home goes in first, then old home gets shaken out so all the roaches end up in the bag with their new home), the bin gets a cleaning and then new bedding – a thick layer of coco peat. This is utilizing the deep bedding principle core to animal raising natural style – but that’s a separate topic altogether.

After cleaning, a thick layer of coir goes down first. this is how the last stuff started.

Now the new roach home (egg cartons) comes out of the black plastic garbage bag and into the bin. The roaches naturally seek the dark safety of the cartons so they are easily moved inside the cartons(which are all glued together for stability).

The roaches in their new home (egg cartons glued together) in their newly cleaned home (aquarium)

Last bit since it’s evening now and they get fed each night – food time! The staple when there are no veggie/meat trimmings is fermented dog food. I put the dog food in a sealed plastic container with some lacto, it ferments for a few days then I feed that to them. They just love the stuff. Doesn’t take much to feed the colony as you can see here.

Feeding time – the lighter beige pieces there are bits of fermented dog food – the roaches love it and it keeps them healthy and growing fast

What a beautiful system… the cleaned out bedding is an incredible nutrient source. It goes into a black plastic bag and gets sealed to kill off the egg cases and beetle larva. Lacto solution is added to facilitate decomposition in the anaerobic conditions. After a few weeks its ready for use! It’s amazing, I pulled out corn cobs that just disintegrated in my hand when I picked them up. The level of decomposition is crazy – only bones left, and not even that many of them considering how many went into it. I’m keeping this compost handy for use in the garden later – it will get mixed with traditional compost – it’s too strong and valuable to waste just by itself.

Share this:

i trust you Gil. but one animal that i am so phobic to is roach. as much as i try to apply whatever i read on your blog, i’ll have to give this a miss. haha. i can still handle worms. but as a home gardener, roach is the last thing i wanna see around the house! *goosebumps!*

but i really salute you and your work. i learn a great deal. this is my favourite go-to garden knowledge site now.

Haha thanks Azlan, this is actually my method.. I hate roaches also, but this species is much better than the house roaches at least, they don’t climb! so it is relatively easy to keep them in the cage..

Wonderful! We all have this idea that cockroaches are disgusting but they’re just another insect and used this way is a great idea. Love your tutorials fellas, so clear and informative and great pics to explain each process.

I’ve been sharing some of your ideas on our Brisbane Local Food group site, hope you don’t mind. I’ve included links back to your site.

Some of our group visited a snail farm about a month ago and it really got me inspired as I can’t keep chooks or quails – have dogs that would kill them, plus don’t know if I could “do the deed” myself – and aquaponics is beyond me, so decided to try snails as a protein I can farm without too much trouble.Early days, but I have the box and am slowly collecting the edible ones out of my garden to go in there to grow into a useful size and hopefully start to breed.

You have some interesting subjects on the site! One of the members was particularly interested in your home made fish fertiliser.
A big rat ate all my snails (babies) and others in the garden. Found his stash of empty shells under the water tank pump shelter.
I’m visiting Glasshouse Gourmet Snails weekend after next to buy some mature stock. Think I’ve managed to poison the rat, no sign of him for about a week, so they should be safe. Plus I need to remember to close the lid at night!

Thanks Lissa glad you’re enjoying our topics. Yeah the fish fertilizer is a popular article, you could use your snails for that you know, and then use the shells in the calphos recipe. You could also use the rat in the fish fertilizer recipe.. Pretty gruesome I know, but better use than poisoning.. catch the rat, blend it, ferment it, and use it on the garden. Hahaha yeah, gruesome, but useful.

My dogs have tried hard to catch the rat and the mice without success. Had to resort to poison in the end. We get cane toads here also (introduced pest). I freeze them to kill them. One of my gardening acquaintances buries their bodies at the bottom of fruit tree holes or similar.
Re the rat – I can see the benefit to the garden, but don’t think I could personally come at blending, but I could bury it!

LITTLE SMELL .. hmmm kinda like my Madagascar Hissing Cockroach, truly this creeper is clean …. unlike those pesky common house roaches. and i’ve read it’s the same with Blatta lateralis, just leave anything and it’ll consume it … and voila! no mess – no smell.

this is the first time i saw your site …. bravo to you Gil and Patrick.

Oo tough one – sorry Bootsah I don’t think they’ll eat the pine cones. I would recommend a woodchipper for those. Gather them all up, run them through the chipper and mix with a really green source like kitchen scraps, lawn trimmings, fresh leaves, fresh manure, etc. You can also ferment the pine cones before adding them to the pile, to help soften them up. But wood chipper would be most effective.
Cheers – Patrick

Willing to try difficult things, but wary. Two questions: I couldn’t follow just how you get the compost out without picking out cockroaches. Can you add some detail for the squeamish?

Second, having just arrived here, it took me a few moments to learn you are in the Philippines. And the cockroaches are on the balcony. I live in the Northeast US, and I assume winter would kill them off (and I’m not sure I could put them in the basement – that squeamish thing again). Any thoughts?

Wait, it’s three questions. For worms, you have to chop up the food scraps very small. I gather not so for the cockroaches?

Thanks for this interesting article! Off to explore the rest of your blog!

Hey Anne, great to have you! Sorry for the late reply! To answer your quesions:

the roaches hide in the egg cartons, which are all glued together. I simply pick out the carton and put it in a plastic bag while I’m cleaning the tank. Almost all the roaches stay in the carton, for the others I use toilet paper rolls to lure them into, then pick them out using those.

I would keep them somewhere with a lamp to keep the tank warm, like in your garage but with a light that keeps it warm enough they won’t die during winter. Don’t worry the lateralis species doesnt climb glass.

Nope, don’t have to chop up scraps for cockroaches, using the “deep bedding” approach I described.

mind boggling when you begin to think laterally about the applications for the use of the material and what you could specifically create ‘food for’ eg: elements high in N P or even K to make specific components for your project.

Patrick, I love this website but I particularly like this write-up on the roaches. I definitely think insects can help the composting process! I do have a few questions for you on this, though.

Why did you choose to go with cockroaches vs. black soldier flies? Also, you stated that you give them various fruits, grains etc.. Are they pretty efficient in digesting cellulose? Finally, do you have a good method for harvesting these guys?

I chose roaches over BSF because here in Manila they are much, much cheaper to get, and easier to keep.
They are OK at digesting cellulose. They just don’t like it that much. They really prefer meats, dairy, fats, etc. But they will eat anything in a pinch except things super high in carbon/cellulose like straw. I do feed them used coffee grounds from Starbucks, after bokashi composting them.
There are several ways to harvest them. So far the easiest has been just grab one of the egg trays from in the tank and shake it over a container, the roaches drop into the new container. Those I feed to Opi, the bearded dragon. There are also auto-sort methods that are pretty awesome, I’m working on those.

Great question John. This is the whole “deep litter” concept promoted by natural farmers, but on the insect scale. If you google ‘deep litter piggery’ or similar you can read about it. It’s basically just a way to keep the environment clean without cleaning it. It’s awesome!! Also, it’s a way to collect all the good droppings, and end up with a decent amount of awesome fertilizer.